How do I add related Data in Microsoft.EntityFrameworkCore.InMemory ?

[JakubK]

Hi, I'm trying to construct DbContext for the sake of automatic tests in my App. I've decided it will be better to use InMemoryDb instead of Mocks.

This is the code I wrote:

var builder = new DbContextOptionsBuilder<AppDbContext>()
    .UseInMemoryDatabase(Guid.NewGuid().ToString());

var ctx = new AppDbContext(builder.Options);

ctx.Users.AddRange(users);
ctx.SaveChanges();

ctx.Books.AddRange(books);
ctx.SaveChanges();

1 User can have N Books. Calling this code ends up with the following exception:

System.InvalidOperationException : The instance of entity type 'User' cannot be tracked because another instance with the same key value for {'Id'} is...

System.InvalidOperationException : The instance of entity type 'User' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap`1.ThrowIdentityConflict(InternalEntityEntry entry)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap`1.Add(TKey key, InternalEntityEntry entry, Boolean updateDuplicate)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap`1.Add(TKey key, InternalEntityEntry entry)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap`1.Add(InternalEntityEntry entry)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.StartTracking(InternalEntityEntry entry)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetEntityState(EntityState oldState, 

I have noticed that when I manually change every ID to be unique between tables, then this exception is not being thrown, but I don't want to do this everywhere.

Is there any way to make EF Core ignore this and go on?

EF Core version: 7.0.0-preview.5.22302.2 Database provider: Microsoft.EntityFrameworkCore.InMemory 7.0.0-preview.5.22302.2 Target framework: .NET 6 Operating system: Windows 10 IDE: Rider

[ajcvickers]

@JakubK I would suggest you read the documentation on change-tracking. Beyond that, there really isn't enough information above to understand what you are attempting to do.

[JakubK]

@ajcvickers all I want to do is to fill this dbcontext with data created earlier. Everything is setup in these arrays being passed as an argument to AddRange method. As I mentioned earlier: This problem occurs when ids are not unique, even outside of single table's scope. Imagine having 1 user with id=1 in users list and 1 book with id=1. This book is related to user. Now adding these 2 entities causes this exception. But changing any of mentioned ids fixes it. I want to avoid this operation.

Basically this exception message complains about book with id=1 being added because there is already user with this id. It does not make sense for me.

[smitpatel]

Imagine having 1 user with id=1 in users list and 1 book with id=1. This book is related to user. Now adding these 2 entities causes this exception.

This is not expected behavior. Please provide a runnable repro code. If you add 2 users both of them having id=1 then it is expected exception as above.

[JakubK]

Okay, nevermind. Code using external library generating the lists was messing with the Navigation Property. Sorry for trouble.